i have a stock 02 F-150 4x4 and im just wondering if when you engage the 4x4 does the rear diff lock completely or if you get one side stuck does it just transfer the power over to the other unstuck side?

 

These trucks were not available from the factory with a locker. You did have the option though of a limited slip. While a limited slip will help limit the 1 wheel peel action they can only take so many LB/FT before the clutch packs slip allowing you to spin only 1 tire. Might want to check the specs on your truck, if you still have the window sticker it should be on there and see if it came with a LS (limited Slip)

 

i dont have the sticker i just bought the truck and was just wondering about it. or is it a posi rear end where if one wheel starts to spin it locks up?

 

Yeah pretty much the same. I think posi was just the name Chrystler had for the same thing. You can add a locker if you would like. They make manual and automatic locking rear diffs for our trucks. Really only needed if you are doing something rather extreme though, my LS in my 06 has been surprisingly effective when compared to ones I have had in other trucks

 

a limitied slip is as the name implies. if the tires slip it might kick in and make it so both tires spin. better for street driving, not great for off road but better than an open diff. lockers lock the two axles together so that both are always turning. the new detroits i believe actually have a ratchiting action that will allow one tire to spin a litte seperatley but generaly lockers lock both together. great for off road, not great for the street. on the door jamb should be a sticker i believe the U axle code is limited slip but i could be wrong. just search on here

 

Actually a posi doesn't lock up or kick in. It has a set of clutches in between the two axles inside the diff that are pressed together. These clutches will hold the axes together so that they spin at the same rate unless there is enough force on one wheel (turning a corner for example) to make it slip the clutches and turn at a different speed, or the clutches are worn out. If your truck has a lot of miles on it and the posi has never been checked or rebuilt it might not be effective anymore. Back when I was racing we used to pack extra clutch disks in these to make the force even greater to resist slipping. GM though has some kind of gear based setup though that will actually lock after a wheel starts to slip I believe...

 

Yeah its actually a mechanical locker. GM uses the code G80 for it